Computing devices have become ubiquitous in almost every environment. Mobile telephones, laptop computers, and tablet computers are commonly used for work and pleasure and often accompany people in many daily activities. People often travel with computers and mobile phones, bring these devices to school, and use these devices in public places. Interacting with these devices has become part of daily routines and accepted social norms.
However, in some situations, the use of computing devices may be restricted or otherwise not permitted for various reasons. For example, the Federal Aviation Agency (FAA) guidelines restrict use of computing devices by passengers during takeoff and landing of commercial aircraft. In some academic environments, use of communicating devices may be restricted at times, such as during an examination.
Other environments may limit use of some functionality of a computing device. For example, a museum may allow use of a mobile phone for text messaging and email, but may restrict use of the device for voice calls and photography.